<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    
</body>
</html>
<script>
    // function rabbit(n){
    //     if(n==1){
    //         return 1
    //     }
    //     return rabbit(n-1)+(n-3)+n
    // }
    // console.log(rabbit(10));

    function rabbit(n){
        if(n==1){
            return 1
        }
        return (rabbit(n+1)+1)*2
    }
    console.log(rabbit(1));
</script>